Currently, LuxCore light source settings are not node-based, they don't support arbitrary textures as input.
For example, in the infinite light properties, I can only specify the file to load and some additional properties: https://wiki.luxcorerender.org/LuxCore_ ... :_infinite
(the infinite light is exposed as "HDRI" mode in the Blender world settings)

However they are standard image maps with all connected pre-processing features available (like channel selection, gamma correction, color average, etc.).
Adding HSV pre-processing and exposing the feature would be quite easy.